The Mathematics
Convert every fractional quote separately before multiplying. For 2/1, 3/1, 1/1 and 5/1, the decimal calculation is 3.00 × 4.00 × 2.00 × 6.00 = 144. Combined decimal odds already include the returned stake, so the equivalent combined fractional price is 143/1. Multiplying the raw fractional profit odds would omit stake rollover and understate the payout. A accumulator is equivalent arithmetically to rolling the entire return from one successful leg into the next, not rolling only the first leg's profit.
Each decimal price = fractional numerator ÷ denominator + 1
Combined decimal odds = product of every leg's decimal price
All-win return = cash stake × combined decimal odds
Profit = return − original cash stake
If any leg loses: return = £0
Worked Example
Worked accumulator example: 2/1, 3/1, 1/1 and 5/1, with a £5 total stake. Decimal multiplication is 3.00 × 4.00 × 2.00 × 6.00 = 144. If all 4 selections win, return is £5 × 144 = £720; profit is £720 − £5 = £715. If any selection loses, return is £0 and the loss is £5. No deductions, dead heats, free-bet conditions or bonuses are assumed.
How do I enter the accumulator inputs?
The form starts with three odds rows. Use Add Selection to create the fourth row for this worked example, and use the remove control to delete a row you do not need. At least two rows remain. Enter fractional prices with a slash in every row and enter the total stake once; adding legs does not multiply the stake.
Use the accepted price for every leg and check that the completed row list matches the slip. Do not enter a quoted combined price into an individual selection row as well as entering the other legs, because that would multiply some prices twice. The calculator does not retrieve starting prices, approve combinations, place bets or know the final results. Its all-win total is a conditional illustration. To compare with a settled ticket, first identify losses, voids and any adjustments to individual prices.
How does a accumulator compare with separate or covered bets?
A four-selection Yankee has eleven components, including all doubles and trebles as well as the fourfold. A fourfold accumulator is only one component. If three of the four horses win, the Yankee can still return money from its surviving lines while the fourfold returns zero. At equal unit stakes the Yankee costs eleven times as much, so compare equal spending limits.
Adding a leg at decimal 2.00 doubles the conditional payout but adds another result that must succeed. Removing that leg halves the conditional payout and removes that requirement. Neither operation demonstrates a better expected return. Bookmaker margins, genuine selection chances and dependence between outcomes are not estimated by this arithmetic widget.
What happens when a accumulator leg loses or is void?
One losing leg makes the accumulator return zero, no matter how many other selections win. Under ordinary void-leg rules a fourfold with one non-runner becomes a treble at the same stake. If the 5/1 selection in this example is void, £5 × 3 × 4 × 2 returns £120 if the remaining three win, rather than the original £720.
The ordinary void-leg arithmetic treats the removed leg as decimal 1.00, leaving the original stake running through the remaining legs. If all legs are void, the usual cash outcome is a stake refund. Ante-post and special-market rules may differ. This form does not provide a void selector; it is better to recalculate the valid remaining combination and confirm the operator's settlement than to input a fictitious winning result.
Which accumulator adjustments need separate checking?
Rule 4 reduces the profit odds of the affected race leg rather than simply cutting the final ticket return by a guessed percentage. For a leg at 4/1 with a 25p deduction, use adjusted decimal odds of 1 + 4 × 0.75 = 4.00, then multiply by the other decimal legs. A dead heat also reduces the return attributable to that leg under the relevant rules. This calculator has no integrated controls for either adjustment.
Each way accumulators are normally two linked lines, win-to-win and place-to-place, not every possible mixed finishing pattern. They cost twice the unit stake and need each race's place terms. Exchange commission, stake-not-returned free bets, promotional insurance, maximum payouts and best odds guaranteed are also outside this form. The reciprocal of the combined odds is only a market-implied percentage. It is not the actual chance of success, and multiplying genuine probabilities would require an independence assumption or a suitable joint model.
Popular questions about this calculator
What is a accumulator bet?
An accumulator is one linked multiple in which every selection must win. Four or more legs are commonly called an acca; doubles and trebles use the same multiplication principle. The stake is placed once on the linked line. Successful early legs do not produce payable singles if a later leg loses; the whole combination must satisfy its winning conditions.
How do I calculate accumulator odds?
Convert each fractional price to decimal, then multiply all decimal prices. For 2/1, 3/1, 1/1 and 5/1, 3.00 × 4.00 × 2.00 × 6.00 gives decimal 144, equivalent to fractional 143/1. Do not multiply fractional numerators alone, because the stake must roll through each leg.
What does the example £5 accumulator return?
At 2/1, 3/1, 1/1 and 5/1, all 4 winners return £720 including the original £5 stake. Profit is £715. If any ordinary leg loses the return is £0. This assumes cash staking and no settlement deductions or promotional conditions.
Does a accumulator pay if one selection loses?
No, not under ordinary all-win terms. One losing leg makes the accumulator return zero, no matter how many other selections win. Under ordinary void-leg rules a fourfold with one non-runner becomes a treble at the same stake. If the 5/1 selection in this example is void, £5 × 3 × 4 × 2 returns £120 if the remaining three win, rather than the original £720. Any insurance or refund promotion is separate from the base bet and needs its own qualifying rules; the calculator does not apply those offers.
What happens to a accumulator with a non-runner?
Under ordinary non-runner rules a void leg is removed and the same stake continues on the smaller multiple. It is not treated as a losing leg. Ante-post and special-market conditions can differ. The widget does not automatically detect withdrawals or provide a void-result switch.
Can I use this accumulator calculator for each way bets?
No. This form calculates a win-only linked line. Each way uses separate win and place multiples, normally settled win-to-win and place-to-place. You need every selection's place fraction and eligibility, and twice the unit stake, rather than the win-only figure shown here.
Does accumulator insurance protect this calculated stake?
Not automatically. Insurance is an operator promotion with qualifying conditions, minimum odds, leg counts and a stated refund form. A refund may be a free bet rather than cash. This calculator contains no insurance control and shows the ordinary all-win cash-stake payout before offers.
Do the accumulator odds show the true chance of winning?
No. Odds supply a conditional payout and a market-implied percentage. They are not calibrated probabilities. Even when genuine single-selection chances are available, simply multiplying them is justified only for independent outcomes; related events require a joint assessment rather than this payout calculator.
Does the accumulator calculator include Rule 4 and dead heats?
No. Those changes must be assessed for the affected leg under the operator's rules. Reducing the final ticket profit with one blanket percentage can be wrong. Use the separate settlement tools for simple single-leg checks, and confirm the complete multiple settlement with the bookmaker.
How much should I stake on a accumulator?
There is no universal safe stake produced by a returns calculator. Decide an affordable total spending limit first, then compare conditional returns without increasing the limit to chase a payout. The full stake can be lost when one required selection fails, even after earlier legs have won.
Official rules and further reading
These operator references explain bet structures and settlement rules. They are not endorsements, and the terms attached to your accepted bet take precedence. Worked amounts on this page are illustrative arithmetic, not live odds or promised outcomes. Only gamble money you can afford to lose; a returns tool does not make a bet safe.